286 H. p. GUSHING — FAULTS OF CHAZY TOWNSHIP, NEW YORK. 



into three divisions — a hilly region in the southwest, a high plain sloping 

 north from the hills, and a strip of lowland of varying width along the 

 lake-shore, whose rise to the level of the high plain is quite abrupt. 

 Chazy township belongs, for the most part, in this latter subdivision, but 

 in its western portion the level rises rapidly to that of the high plain to 

 the west. 



The minor topographic features of the township are dependent to a 

 surprising degree on the faults to be described. These features are more 

 or less obscured by drift, but in the vicinity of Chazy village this cover- 

 ing is so much less marked than elsewhere along the low strip that 

 the relations can be readily worked out. The dip here is frequently 

 pronounced, so that the strata outcrop in linear ridges whose crests are 

 the cut-off edges of the various more resistant layers. When followed 

 along the strike, these ridges are found to be sharply intersected at vari- 

 ous intervals by low marshy tracts, beyond which other ridges appear in 

 like manner, but do not correspond with their predecessors. Many of 

 the lines of faulting to be described are occupied by marshes of this char- 

 acter. Furthermore, the main streams occupy fault-lines to a very great 

 extent. 



The Formations represented. 



Leaving out of consideration the Pleistocene deposits, the geologic 

 formations exposed at the surface in the township may be tabulated as 

 in the adjacent table. 



Of these formations the Chazy and the Black River limestones are well 

 exposed, are everywhere fossiliferous and were therefore very serviceable 

 in working out the stratigraphy. This was true in a marked degree of 

 the Black River limestone, which, due to its slight thickness, furnished 

 an especially valuable datum point wherever it appeared. On the other 

 hand, the Trenton and Calciferous are but meagerly and unsatisfactorily 

 exposed, while the frequent outcrops of the Potsdam are of little serv- 

 ice, owing to the lithologic similarity of the mass, the scarcity of fossils 

 and the lack of exact knowledge of its total thickness. This latter must 

 itself be very variable in the region, as the Potsdam is a shore deposit 

 laid down on an uneven floor. One exception must be noted to this 

 general statement concerning the Potsdam, namely, that the passage- 

 beds, separating it from the Calciferous are lithologically distinct from 

 either, and it is believed furnish a recognizable stratigraphic horizon. 

 Mention should be made here of the admirable stratigraphic work done 

 on the Chazy in the vicinity of Chazy village by Messrs Brainard and 

 Seeley, which served as a starting point for this investigation, and to 

 which the reader is referred for details.* 



*Am. Geologist, November, 1888, pp. 323-330. 



